Centrifugal separator



United States Patent 0 3,361,264 CENTRIFUGAL SEPARATDR Johann Peter Quetsch, Berghausen, Kreis Karlsruhe, Germany, assignor to Ernst Heinkel Motorenbau, G.m.b.I-l., Karlsruhe, Germany Filed July 25, 1966, Ser. No. 567,775

Claims priority, application Germany, July 27, 1965,

H 56,702 8 Claims. (Cl. 21tl372) ABSTRACT OF THE DISCLOSURE A centrifugal separator in which a plurality of elongated guide vanes each composed of a plurality of sections extend in longitudinal direction and transversely spaced from each other between the outer substantially conical surface of a carrier and the inner surface of a conical sieve means surrounding the carrier and rotatable with the same about a vertical axis so as to divide the space in a plurality of channels, and in which the sections of the guide vanes can be adjusted relative to each other to there by change the path of material to be centrifuged as it passes in downward direction through the channels.

The present invention relates to centrifugal separators in general, and more particularly to improvements in centrifugal separators of the type which may be utilized for segregating minute solid particles from a liquid carrier.

When a mixture or suspension contains exceptionally small solid particles, it is very difiicult to properly segregate such particles by centrifugal force. The problem is especially acute when a centrifugal separator is to be used for segregation of solid particles from different types of suspensions, i.e., from suspensions wherein the solids do not have the same size. It is well known that a suspension can be properly segregated into a solid fraction and a liquid fraction if the length of intervals during which the fractions remain in the centrifugal separator is a function of the size and certain other characteristics of the solids. If the dwell of successively admitted increments in the separator is too short, only a small percentage of solids will be segregated from the liquid fraction. On the other hand, and if the dwell is too long, the filter or filters of the separator will be clogged with solids and must be exchanged after relatively short periods of use.

It is already known to utilize in such centrifugal separators a set of guide vanes which impel portions of the suspension to travel in paths of predetermined length and to thus remain in the separator for a predetermined period of time. The configuration of such vanes is of importance in determining the dwell of successive increments in the treating zone, and such configuration can also inlluence the separating action in other respects. A serious drawback of such conventional apparatus is that, once installed, the blades will assume a given form and can be used with maximum efficiency only for segregation of a certain type of solids.

Accordingly, it is an important object of the present invention to provide a centrifugal separator which can be readily converted for treatment of different types of mixtures, particularly for segregation of smaller or larger solid particles which are suspended in a liquid carrier.

Another object of the invention is to provide a novel system of guide vanes for use in a centrifugal separator of the just outlined characteristics.

A further object of the invention is to improve the construction and operation of a centrifugal separator of the type wherein all of the rotary parts are driven at the same speed.

An additional object of the invention is to provide a novel assembly of adjusting elements which may he utilized to regulate the position and/ or configuration of guide vanes in a centrifugal separator of the above-outlined characteristics.

A concomitant object of the invention is to provide a centrifugal separator which can be readily taken apart to afford access to adjustable components therein and which is constructed and assembled in such a way that each portion or increment of a mixture which is admitted into the treating zone of the separator is treated with the same degree of intensity.

Briefly stated, one feature of my invention resides in the provision of a centrifugal separator which is particularly suited for segregating small solid particles from a liquid fraction. The novelty resides mainly in the provision of a carrier which is rotatable about a predetermined axis and has an external surface preferably diverging from one to the other axial end of the carrier, a plurality of elongated guide vanes adjacent to the external surface and preferably extending from the other and at least to the one axial end of the carrier to define between themselves a plurality of distinct channels in which the solid particles may advance in a direction from the one toward the other axial end of the carrier, at least one of the vanes com-prising a plurality of relatively movable sections, and adjusting means for changing the position of such vane sections with reference to each other to thereby change the configuration of the vanes and of the channels with resultant influence upon the separating action.

In accordance with a presently preferred embodiment of my invention, the adjusting means comprises one or more annular elements which are concentric with and rotatable relative to but should not move axially of the carrier. The articulate connections between the adjusting elements and the sections of one, two or all of the vanes are preferably such that each such section is turnable about an axis which is substantially normal to the external surface of the carrier.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved centrifugal separator itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of a specific embodiment with reference to the accompanying drawings, in which:

FIG. 1 is an axial section through a centrifugal separator which embodies my invention;

FIG. 2 is a side elevational view of the carrier for a set of adjustable guide vanes, a portion of the carrier being broken away; and

FIG. 3 is a top plan view of the structure shown in FIG. 2.

Referring first to FIG. 1, there is shown a centrifugal separator which may be used with particular advantage to segregate minute particles which are suspended in a liquid. The separator comprises an upright drive shaft 1 whose upper end portion carries a hub or boss 45 forming part of a conically outwardly and downwardly diverging carrier 5. The drive shaft 1 extends through a supporting structure 2 which accommodates an antifriction bearing 3 adjacent to the lower axial end of the hub 4.

In accordance with my present invention, the external surface of the carrier 5 supports several sets of composite guide vanes or blades 6 some or all of which are composed of several sections 6a. The sections 6a may but need not be straight and the vanes 6 preferably resemble helices (see FIGS. 2 and 3) which are adjacent to the external surface of the carrier 5 and extend upwardly from the lower axial end toward and beyond the upper a, v.5 axial end of this carrier. The upper end portions of the vanes 6 are surrounded by a retaining ring a for a conical sieve '7 surrounding a foraminous foil or sheet The means for fixing the sieve 7 in the axial position shown in FIG. 1 comprises a second ring it) which is screwed, bolted or otherwise detachably affixed to the ring 5a. A tubular inlet 11 is disposed above the hub 4 and serves to admit the suspension into the space between the upper end portions of the vanes 6. The external surface of the carrier 5 further supports an annular baffle or weir 18 which extends toward but short of the forarninous sheet 8 and serves to obstruct the progress of solid particles toward the larger diameter end of the carrier. In other words, the sheet 8 and the bafile l8 define between themselves a relatively narrow annular gap for the passage of the solid fraction and of some liquid fraction, namely, of that part of the liquid fraction which was not caused to penetrate through the sheet 8 and the sieve 7 in a zone located above the bafile 18. Such sections 6a of the vanes 6 which are adjacent to the baffle 18 are formed with suitable cutouts as clearly shown in FIG. 1.

The external surface of the sieve 7 carries stiffening ribs 9 which may be located in planes including the axis of the drive shaft 1.

The liquid fraction accumulates in a first chamber which surrounds the sieve '7 and is provided with an outlet 17. This outlet is adjacent to an annular partition 16 which separates the chamber 15 from a solids-collecting chamber 14. The latter communicates with the lower ends of channels extending between the adjoining vanes 6. The chamber 14 is disposed between an outer cylindrical wall 12 and an inner cylindrical wall 13 which latter surrounds the supporting structure 2 for the drive shaft 1.

The carrier 5 further supports a set of annular adjusting elements 19 (see FIGS. 2 and 3) which are articulately connected with the sections 6a of the vanes 6 and are rotatable on but cannot move axially of the carrier 5. For example, portions of the elements 19 may extend into grooves machined into the external surface of the carrier 5. By the simple expedient of changing the angular position of one or more adjusting elements 19, the operator can rapidly and accurately adjust the configuration of the vanes 6 so that such vanes will bring about optimum separation of a given type of solid particulate material from the liquid fraction.

The annular adjusting elements 19 will be moved to desired angular positions prior to admission of a certain suspension. Such movements of the elements 19 will bring about corresponding changes in the configuration of vanes 6, i.e., such vanes may form straight blades which are located in planes including the axis of the shaft 1, they may resemble more or less pronounced helices, or they may form a cascade with strongly pronounced transitions between the individual sections. In other words, each vane may form a blade with more or less pronounced transitions between its sections 6a. It was found that, by resembling a cascade or zig-zag, the vanes are better suited to break up the flow of solid particles toward the chamber 14 and to insure expulsion of a greater percentage of the liquid carrier.

By appropriate selection of the configuration of the vanes 6, the operator can determine the length of intervals during which the solid particles entering at 11 will remain in the channels between the vanes. The length of such intervals depends on the configuration of channels and on the inclination of vanes with reference to the axis of the separator.

The carrier 5 may support a single adjusting element 19 or two or more adjusting elements. The accuracy of adjustment and the number of different vane forms will increase if the carrier 5 supports a relatively large number of adjusting elements 19 which may but need not be equidistant from each other. The articulate connections between the sections 6a and the respective adjusting elements 19 are preferably such that the sections 6a are roclrable about axes which are normal to the external surface of the carrier 5.

The vanes 6 and the adjusting elements 19 preferably consist of suitable synthetic plastic material which does not react with the ingredients of the suspension. The separator may be furnished with one or more sets of spare vanes 6 or with spare sections 6a so that, should it become necessary, the operators may utilize different types of vanes in connection with different types of suspensions.

Another important advantage of my separator is seen to reside in that the foraminous body 8 can rest directly on the exposed edge faces of the vanes 6 so that the channels between the adjoining vanes are fully separated from each other. This means that the solid and/or liquid fraction cannot wander from channel to channel and that each portion or increment of the suspension is treated to the same extent. In many presently known centrifugal separators wherein the sieve rotates with reference to the carrier for vanes, the presence of narrower or wider gaps between the two relatively moving parts is unavoidable so that the fractions can wander from channel to channel. Such wandering of fractions subjects the sieve to excessive specific stresses which exert an adverse influence on the separating action.

My present invention is based in part on the following considerations:

if a suspension is treated in a centrifugal separator which does not have guide vanes, the solid particles which are caused to travel around a conical carrier describe arcuate paths whose configuration depends on the rotational speed of the carrier and on the specific characteristics of the solid ingredient. in other words, the shape of the paths is indicative of the type of solids in the suspension. Now, and in order to enable the apparatus to utilize a very simple drive which need not rotate at two or more different speeds, optimum separation of solid particles be achieved if, at a given speed, the shape of paths in which the solids travel (namely, the shape of channels between the guide vanes 6) is selected in such a way that it insures a dwell of desired duration, This is achieved by utilizing adjustable guide vanes whose configuration can be selected at will and with little loss in time because the vanes 6 and the adjusting elements 19 are readily accessible upon detachment of the perforated bodies 7 and 8. In many presently known centrifugal separators with guide vanes, the shape of guide vanes is selected in such a way that they insure optimum separation of a certain type of solid particles so that the separating action is less eihcient if the size of solid particles is either above or below an average size. The separator of my invention can be readily adjusted so that it will bring about optimum separation of solids regardless of their size, as long as the adjustments in the configuration of vanes 6 are carried out with a View to insure that the dwell of suspension in the channels between the vanes 6 will be of such length as is most satisfactory for a given type of suspension.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new desired to be protected by Letters Patent is:

1. A centrifugal separator, particularly for segregating solid particles from a liquid fraction, comprising, in combination, a carrier having a substantially vertical axis and an external surface tapering from the lower towards the upper end thereof; sieve means coaxial with said carrier and surrounding the external surface of the latter spaced therefrom; a plurality of elongated guide vanes extending transversely spaced from each other between said external surface of said carrier and said sieve means and in longitudinal direction from said lower at least to said upper end of said carrier so as to define between the external surface of said carrier and said sieve means a plurality of channels, at least some of said guide vanes comprising a plurality of relatively movable sections; adjusting means for changing the position of said sections with reference to each other and comprising at least one adjusting element surrounding said carrier and being movable only in circumferential direction thereof; drive means connected to said carrier and sieve means for simultaneously rotating the same about said axis; feeding means for feeding a suspension of solid particles in a liquid into the upper end of the space between the external surface of said carrier and said sieve means so that during rotation of said carrier and sieve means liquid will pass through the latter while the solid material will travel in downward direction through said channels; and means for collecting the separated liquid and solids.

2. A structure as set forth in claim 1, wherein said external surface of said carrier is substantially frustoconical and wherein the inner surface of said sieve means is substantially equally spaced from said external surface of said carrier.

3. A structure as set forth in claim 2, wherein the upper end of said sieve means is located at a higher elevation than the upper end of said carrier, wherein said guide vanes extend to said upper end of said sieve means, and wherein said feeding means communicates wtih the space between the upper end of said sieve means and the upper end of said carrier.

4. A structure as set forth in claim 1, wherein at least some of said vanes are curved.

5. A structure as set forth in claim 1, wherein said sections are turnable with reference to said adjusting element about axes which are substantially normal to said external surface.

6. A structure as set forth in claim 2, wherein each of said vanes comprises a plurality of relatively movable sections, said adjusting means comprising a plurality of annular adjusting elements concentrically surrounding said carrier and each articulately connected with at least one section of each vane, said adjusting elements being rotatable with reference to said carrier.

7. A structure as set forth in claim 6, wherein said adjusting elements are arranged to change the configuration of said vanes in response to angular movement with reference to said carrier so that each such vane may assume a plurality of shapes with more or less pronounced transitions between the respective sections.

8. A structure as set forth in claim 1, further comprising bafile means provided intermediate the axial ends of said carrier to obstruct the progress of solid particles through said channels.

References Cited UNITED STATES PATENTS 618,814 1/1899 Darby a- 2l0377 X 871,517 11/1907 McDaniel 20374 X 1,520,467 12/1924 Frantz 210-372 SAMIH N. ZAHARNA, Primary Examiner. J. L. DE CESARE, Assistant Examiner. 

